Refueling of a hydrogen vehicle is basically concerned with how the refueling can performed safely and without over-fueling the vehicle tank.
One method is described in SAE J2601 directing how a refueling can be safely executed without the risk of over-fueling the vehicle tank.
Various methods known within the art may be attempted adapted to comply with the above standard. One such method is described in EP1336795. Here an electric controller has knowledge of the rated density of a full vehicle tank, knowledge which is obtained from the manufacture of the tank. The electric controller is then periodically during the refueling, based on temperature and pressure signals from inside the tank, calculating the density in the receiving tank. When the calculated density is less than the tank rated density a flow is allowed to the tank and when the calculated density is higher than the tank rated density the flow is discontinued. When the density in the tank is equal to or higher than the rated density, the electric controller wait for the instrument to settle and if the density is still above rated density the refueling is complete. If not, the refueling is again resumed. In this way over time, the calculated density equals the tank rated density resulting in a full receiving tank.
The prior art including EP1336795 suffers from drawbacks that e.g. information is needed of the vehicle tank design and that calculation of density during the refueling process is required.